Conduit heating apparatus

ABSTRACT

An apparatus for heating portions of first and second separate plastic conduits. The apparatus has first and second heating heads each having a heating face operably connected to respective first and second separate heating elements. An insulating element is positioned between the first and second heating heads and separate controls are connected to the heating elements for separately controlling the temperature of each heating face.

I United States Patent 1 1 1 1 1,682 Chester et al. 51 Jan. 16, 1973 CONDUIT HEATING APPARATUS [56] References Cited [75] Inventors: Milton L. Chester, Titusville, Pa.; UNITED STATES PATENTS gu sanders oklamma 3,6l0,885 10 1971 Zingg ..219 445 3,303,324 2/1967 Appleman.... ..2l9/345 73 Assignee: Phmips Pe'ro'eum Company 3,0l3,925 I2/l96l Larsen ..285/423 X [22] Filed: Jun 1 1 Primary Examiner-C. L. Albritton [2]] Appl NOJ 154,134 AttorneyJ. Arthur Young et al.

[57] ABSTRACT [52] US. Cl. "219/535, 156/433, 219/538, An apparatus for heating portions of first and Second 285/286 285/423 separate plastic conduits. The apparatus has first and [5]] Int. Cl. ..Ho5b 1/00 e ond heating heads each having a heating face [58] Field of Search ..2l9/200, 201, 209, 535, 536,

operably connected to respective first and second separate heating elements. An insulating element is positioned between the first and second heating heads and separate controls are connected to the heating elements for separately controlling the temperature of each heating face.

6 Claims, 5 Drawing Figures POWER SOURCE PATENTEDJAH 16 I975 POWER SOURCE -|6 POWERSOURCE FIG. 4

INVENTORS M. L. CHESTER B. J. SAN ERS 7} w ATTORNfYS CONDUIT HEATING APPARATUS It is sometimes desirable .to join by fusion a first plastic conduit having one fusion temperature to a second conduit which has a different fusion temperature. When the fusion temperatures of the conduits are relatively close one to the other, this can be accomplished by means known in the art. The resultant join of fusion is, however, sometimes less than desirable in appearance, strength, and other qualities. 1

This invention therefore resides in an apparatus having first and second heating heads which have separate heating faces that are insulated one from the other and are separately controlled for heating each face to the preselected temperature that is ideally suited for the particular conduit on which it is to be utilized.

Other aspects, objects, and advantages of the present invention will become apparent from a study of the disclosure, the appended claims, and the drawing.

The drawings are diagrammatic views in partial section of the apparatus of this invention.

FIG. 1 shows one embodiment of the apparatus of this invention,

FIG. 2 shows a view taken along line 2-2 of FIG. 1,

FIG. 3 shows a view takenalong line 33 of FIG. 1,

FIG. 4 shows a heating element of another embodiment, and

v FIG. 5 shows another embodiment of the apparatus.

Referring to FIG. I, the apparatus has first and second heating heads 2,4 that are connected to and separated by an insulating element 6 positioned therebetween. Each heating head 2,4 has a heating face 8 associated with first and second separate heating elements 12,14. These elements 12,14 can be constructed in any manner known in the art for increasing the temperature of a member associated therewith. Preferably, these heating elements 12,14 are high resistance electric wires, as known in the art. The first and second heating elements 12,14 are preferably connected to a power source 16 through first and second separate controlling elements 18,20. Each of the controlling elements 18,20 is separately connected to a respective one of the heating elements 12,14. Where the power source 16 is an electrical power source, for example, the controlling elements can be rheostats, for example.

The heating faces 8 and associated elements 12 or 14 can be of various configurations that are dependent upon the construction of the conduit to be heated and the type of fusion joint that is desired to be formed. FIGS. 1-4 show examples of the different heating face construction with associated heating elements.

Referring to FIGS. 1 and 2, conduit 22 has a bell end configuration and conduit 23 has a spigot end, the first heating head 2 has an outwardly extending protrusion 24 of a diameter less than the inside diameter of the conduit 22 to be heated for insertion of said protrusion 24 within an end portion 28 of said conduit 22 and heating said end portion 28. Here the associated heating element 12 extends into the protrusion 24 for heating the belled portion 28 and end 30 of the conduit 22. Preferably in this construction, the heating element is adjacent only the walls 32 of the protrusion and a portion of the first heating head immediately surrounding said protrusion 24. The second heating head 4 has a ringlike protrusion 24' of a diameter greater than the outside diameter of the conduit 23 to be heated after insertion in the ringlike protrusion 24. Here the associated heating element 14 extends circumferentially inside ringlike protrusion 24' for heating the end portion 31 of the conduit 23.

Referring to FIGS. 1 and 3, end portion 26 is planar and does not have a heating element 14' associated therewith. In this embodiment, the protrusion 24' is utilized to guide and center the conduit on the heating head 4 with substantially only the end portion 31 of the conduit being heated for fusion of the conduits, for example.

Referring to FIG. 4, heating of only the end of the conduit can be accomplished by providing a heating face 8 of planar configuration. In this embodiment, the heating element 14 can be of ring configuration having a matching configuration relative to the conduit end or can be of generally circular configuration covering the entire end area of the conduit. In this embodiment, conduits having plain ends of the same diameter provide a butt fusion point.

Referring to FIG. 5, the heating face 8 of one of the protrusions is of a curvilinear configuration for contacting and heating a portion of a sidewall 34 of a conduit 22 for fusing another conduit or fitting to said sidewall. In this embodiment, the associated heating element 12 is preferably the configuration of the portion of the protrusion 24 which contacts the conduit 22 during heating thereof.

The insulating element can be formed of asbestos or other insulating materials as known in the art.

It should be understood that the configuration of the heating faces 8 and associated heating elements can be as shown above or of other configurations to provide heat to the areas that are to be joined. One example, for instance, would be a heating face and associated ele ment which would encompass the outer periphery of the conduit. It is also preferable that the first heating head and its associated apparatus be of a configuration relative to the second heating head and its associated heating element 14 and heating face 8 such that after simultaneously heating the end portions of the two conduits, said two conduits are joined one to the other. Of course, the configuration can be not relatively similar and can be used for simultaneously heating conduit end portions that are not to be joined one to the other but are to be joined to other conduits.

Examples of the different conduits each having different temperatures of fusion such that each can be heated to their selected temperature simultaneously by the apparatus of this invention are:

Example Temperature of Material Heating Face 8 A. Ultra High Molecular Wt. and Very High Molecular Wt. (i.e., greater than 250,000) high density polyethylene 475500F B. Medium density polyethylene 450-470F C. Low density polyethylene 350-400F Conduit of material A can be joined to material B. Conduit of material B can he joined to material C. Conduit of material C can be joined to material A.

controlling elements 18,20 are then adjusted to bring the heating face 8 of each heating head 2,4 to the temperature corresponding to the preselected temperature desired for fusing the conduit. After the face 8 of each heating head 2,4 has reached its preselected temperature, the conduit end portions are brought intocontact with their respective heating face for raising their temperatures to the selected value. The conduits are thereafter removed from contact with the apparatus and brought together for fusing one to the other.

Other modifications and alterations of this invention will become apparentto those skilled in the art from the foregoing discussion and accompanying drawing, and it should be understood that this invention is not to be unduly limited thereto.

We claim:

1. An apparatus for heating protrusions of first and second separate plastic conduits to their temperature of fusion for joining one conduit to the other, comprising:

a first heating head having a heating face of a ring configuration of dimensions sufficient for encompassing and contacting the entire end portion of the conduit to be heated;

a second heating head having a heating face with an outwardly extending protrusion of a diameter less than the inside diameter of one of the conduits to be heated for insertion within and contacting an end portion of said conduit for heating said end portion;

first and second separate heating elements associated with the faces of the respective first and second heating heads for heating said faces;

an insulating element being positioned between the first and second heating elements and connected to the first and second heating heads for insulating the heating elements one from the other; and

first and second controlling means each connected to a respective one of the heating elements for separately controlling the temperature of said first and second heating faces.

2. An apparatus, as set forth in claim 1, wherein the controlling means are separate rheostats each operably connected to respective heating elements.

3. An apparatus, as set forth in claim 1, wherein the insulating element is formed of asbestos.

4. An apparatus, as set forth in claim 1, wherein the first heating element is of a ring configuration of dimensions sufficient for positioning said first heating element within the first heating head and encompassing the end portion of the conduit to be heated.

5. An apparatus, as set forth in claim 1, wherein the second heating element is of a ring configuration of dimensions sufficient for positioning said second heating element within the protrusion portion of the second heating head and insertion within the end portion of the conduit to be heated.

6. An apparatus, as set forth in claim 5, wherein the cross section. of the second heating element is of a general 2" configuration for heating the end portion, end, and shoulder of a conduit having a belied end portion. 

1. An apparatus for heating protrusions of first and second separate plastic conduits to their temperature of fusion for joining one conduit to the other, comprising: a first heating head having a heating face of a ring configuration of dimensions sufficient for encompassing and contacting the entire end portion of the conduit to be heated; a second heating head having a heating face with an outwardly extending protrusion of a diameter less than the inside diameter of one of the conduits to be heated for insertion within and contacting an end portion of said conduit for heating said end portion; first and second separate heating elements associated with the faces of the respective first and second heating heads for heating said faces; an insulating element being positioned between the first and second heating elements and connected to the first and second heating heads for insulating the heating elements one from the other; and first and second controlling means each connected to a respective one of the heating elements for separately controlling the temperature of said first and second heating faces.
 2. An apparatus, as set forth in claim 1, wherein the controlling means are separate rheostats each operably connected to respective heating elements.
 3. An apparatus, as set forth in claim 1, wherein the insulating element is formed of asbestos.
 4. An apparatus, as set forth in claim 1, wherein the first heating element is of a ring configuration of dimensions sufficient for positioning said first heating element within the first heating head and encompassing the end portion of the conduit to be heated.
 5. An apparatus, as set forth in claim 1, wherein the second heating element is of a ring configuration of dimensions sufficient for positioning said second heating element within the protrusion portion of the second heating head and insertion within the end portion of the conduit to be heated.
 6. An apparatus, as set forth in claim 5, wherein the cross section of the second heating element is of a general ''''Z'''' configuration for heating the end portion, end, and shoulder of a conduit having a belled end portion. 